BOOK REVIEWS

Identification Guide to the Aculeata of the Nansei Islands, Japan

by Seiki Yamane, Shuichi Ikudome & Mamoru Terayama

On current knowledge, the largest phylum of animals is the Arthropoda, in which the largest class is the Insecta, in which the second largest order is the Hymenoptera, with some 120,000 species known and perhaps millions undescribed. About half of the known species are in the infraorder Aculeata, including the familiar stinging wasps, ants and bees. The taxonomic scope, then, of this book is ambitious. The geographic scope is the chain of islands between Taiwan and Japan, from 24^° to 31^° N, including over 150 islands in the Ryukyus as well as the outlying Senkaku and Daito groups. They comprise Japan’s tropical frontier, and support almost half of its aculeate species on less than 1% of its land area.

The book is bilingual, in Japanese and English, and aims to assist both specialists and general naturalists in identifying these ecologically important insects. The bulk of it is keys: to super-families, to families, to genera and to species and descriptions, followed by descriptions at each taxonomic level. What makes it more approachable than most such keys is the clear line drawings at each couplet, giving even a newcomer the best chance of successful identification. Twenty-four colour plates illustrate a selection of species from 22 of the 26 families: most show mounted specimens, but many of the ants, and some vespids, megachilids and others, are shown in life. Preceding the keys are introductory chapters on phylogeny, morphology and biogeography. The appendices include a spreadsheet of distribution of the species on the islands, a very useful addition for those wanting more depth.

I cannot fully evaluate the keys without a trip to the islands (sadly beyond the Porcupine! expense account), but those for the ants, the only group with which I can claim a familiarity, seem exceptionally clear and simple to follow. The higher-level keys will be useful to students and naturalists far beyond the Nanseis. 

From one to half a million years ago and more recently, Taiwan and the southern and central Ryukyus were joined to the mainland, whereas the northern Ryukyus, across the Tokara Strait, were joined to Kyushu. Still, at least in the case of the ants the southern islands do not contain much of the tropical faunal element that would occur at the same latitude in Guangdong, while the subtropical elements tend to occur throughout the chain. More particular differences from the mainland fauna include a paucity of Pheidole and Polyrhachis species, balanced by a wealth of Aphaenogaster. Most of the Palaearctic species, of Lasius, Formica and Myrmica, are confined to the taller islands of Yakushima and the Tokara group; such islands also support most of the endemic aculeates. Thus the influence of altitude on the islands’ ant fauna appears at least as strong as that of location.

For interpreting such distribution patterns, inclusion of the islands’ altitudes in the appendix would have been helpful, as would brief information on their vegetation. As Skip Lazell would doubtless point out, species-altitude graphs might have been more illuminating than the species-area graphs shown. On the identification front, species descriptions are inevitably brief, and for the ants I would perhaps have included the measure of alitrunk length as well as total length, which is far more variable within a species. But overall the inconveniences of the book – typographical errors, the lack of a subject index to accompany the taxonomic one, the ‘late entrants’ in the Appendix – are very minor for such a wide-reaching tome.

On the whole this is a superb book, which sets the standard for Asia. The authors, particularly Professor Yamane, work tirelessly to help other would-be specialists in the region to attain such standards, and this book is just one example of their effort. It is also an important reference for those of us seeking a better general understanding of subtropical ecosystems or biodiversity. We haven’t understood much until we’ve got to know the Hymenoptera.

The book runs to almost 900 pages in all, and comes hardbound with a strong case. It is available from Mr. Haruo Tamiya, Hokkaido University Press, Kita-9, Nishi-8, Kita-ku, Sapporo, 060-0809 Japan (up-tamiya@coop.hokudai.ac.jp). Ordering through Prof. Yamane (sky@sci.kagoshima-u.ac.jp) may permit a discount rate. The normal price is 26,500 yen (about HK$1960), the discount rate 21,200 yen – a heavy price, but a heavy book. I shudder to think what the companion volume for continental China would weigh. In the authors’ words: “When comparative work of species from this region and those from Taiwan and continental China is completed, this book should be completely revised.” However hard we work towards making it redundant in this way, the Nansei book will have regional importance for many years.

John R. Fellowes

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